It is often necessary to make an adhesive bond to an animal body, usually a human body, in order to attach a medical appliance or device. Although many adhesive compositions are known, very few of these are suitable for application to human skin. The requirements for such as adhesive are stringent; it must bond strongly to human skin, yet be peelable without damage to the skin's surface. Furthermore, it must cause no inflammation, even on prolonged contact, and should have a minimal tendency to provoke allergy. It must be free of any substances which may be carcinogenic. The requirement to be non-allergenic is particularly difficult to meet, and most adhesives currently available are prone to cause allergies in a significant proportion of patients. When the patient has a tendency to allergy, it may be necessary to test a number of adhesives before one is found which is compatible. This is time-consuming for the doctor, and in the meantime the patient is caused distress by allergic reactions.